I am copying straight from Canada Government web site. The Arrive Can app must be used to upload your covid 19 pre cruise test before embarkation. This requirement also applies to Canadian residents.
Providing proof of vaccination
You’re required to upload your proof of vaccination into ArriveCAN before:
you enter Canada, or
embarking on a cruise that is travelling outside Canadian waters (for example, if docking in the United States for a shore excursion) or a cruise, or
embarking on a cruise that will dock in Canada at any point in the itinerary
This applies to all travellers, including Canadians. ArriveCAN is mandatory and free for all travellers entering Canada, regardless of citizenship or vaccination status.